Power to various components of an electronic system, such as a computer system or other type of electronic system, is provided by a power supply in the electronic system. The power supply includes a power source, which can include an alternating current (AC) source, such as that provided by wall power outlets. Typically, the AC power source is provided to an input of an AC power adapter, which converts the AC input to a direct current (DC) output voltage provided to an electronic system. Another type of power source for an electronic system is a battery, which provides one or more output DC voltages for the electronic system.
The power supply of an electronic system also includes one or more DC-DC converters for converting an input DC voltage (such as that provided by a battery or by the AC power adapter) to one or more other (usually different) DC voltages that are used to power the components of the electronic system.
Some DC-DC converters include a pulse-width modulation (PWM) circuit that controls the duty cycle of a switch in the converter to regulate the output DC voltage(s). The duty cycle of a switch refers to the amount of time that a switch is on versus the amount of time that the switch is off. For example, a 10% duty cycle means that the switch is on 10% of the time and off 90% of the time. Typically, the PWM circuit of the converter varies the duty cycle of the switch in response to fluctuations in the output DC voltage of the converter. By adjusting the duty cycle, more or less energy can be delivered so that the output voltage can be increased or decreased as appropriate.
Some DC-DC converters are capable of producing the same output voltage level for a relatively wide range of input voltage levels. Such DC-DC converters are referred to as wide-range DC-DC converters. Some conventional wide-range DC-DC converters rely upon varying PWM duty cycles to achieve an output voltage level for multiple input voltage levels. Such wide-range DC-DC converters tend to be inefficient, due to energy losses that occur in the DC-DC converter as a result of PWM duty cycle variation.
To address this issue, some electronic systems employ different power supplies depending upon the supply voltage of each electronic system. For example, a 12-volt electronic system would use a first power supply, while a 48-volt electronic system would use a second, different type of power supply. As a result, the system manufacturer has to maintain two different part numbers for the two different types of power supplies. In addition to increased costs associated with a larger inventory of parts, using different types of power supplies also reduces flexibility since the power supply for the 12-volt electronic system cannot be used in the 48-volt electronic system, and vice versa.